Floatation of sulfide ores

ABSTRACT

An improvement in the concentration of ores by flotation which comprises subjecting a sulfide ore in the form of a pulp to a flotation process in the presence of an effective quantity of a flotation collector corresponding to the formula WHEREIN R and R2 are hydrocarbyl groups and R1 represents an alkylene or heteroalkylene group. Certain of the indicted compounds provide for enhanced recovery and/or selectivity of sulfide minerals of Cu, Zn, Mo, Co, Ni, Pb and As over iron sulfide. The compounds are also useful as fungicides and herbicides.

United States Patent [72] Inventor Guy 11. Harris Concord, Calif. 21Appl. No. 796,159 [22] Filed Feb. 3, 1969 [45] Patented July 6,1971 [73]Assignee The Dow Chemical Company Mldland, Mich.

[541 F LOATATION OF SULFIDE ORES 10 Claims, No Drawings [52] U.S.Cl209/166, 200/455 [51] 1nt.Cl B03d1/02, C07c 153/07 [50] Field ofSearch209/106, 167; 252/61; 260/455 56] References Cited UNlTED STATES PATENTS1,640,218 8/1927 Sayre 209/166 1,674,166 6/1928 Douglass 209/1662,691,635 10/1954 Harris 209/166X 2,835,625 5/1958 Lo 260/455X 3,012,05312/1961 Lesslie 260/455 3,224,863 12/1965 DAmico 260/455X 3,290,35112/1966 McKay 260/455 FOREIGN PATENTS 750,568 6/1956 Great Britain260/455 1,179,312 12/1958 France 260/455 Primary Examiner-Tim R. MilesAssistant Examingr -Robert l-lalper Azrorn vs-Griswold and Burdick andBruce M. Kanuch ABSTRACT: An improvement in the concentration of ores byflotation which comprises subjecting a sulfide ore in the form of a pulpto a flotation process in the presence of an effective quantity ofaflotation collector corresponding to the formula wherein R and R arehydrocarbyl groups and R represents an alkylene or heteroalkylene group.Certain of the indicted compounds provide for enhanced recovery and/orselectivity of sulfide minerals of Cu, Zn, Mo, Co, Ni, Pb and As overiron sulfide. The compounds are also useful as fungicides andherbicides.

FLOATATION OF SULFIDE ORES BACKGROUND Flotation is a process of treatinga mixture of finely divided mineral solids, e.g., a pulverulent oresuspended in a liquid whereby a portion of such solids are separatedfrom other finely divided mineral solids, e.g., clays and other likematerials present in the ore, by introducing a gas (or providing a gasin situ) in the liquid to produce a frothy mass containing certain ofthe solids on the top of the liquid, and leaving suspended (unfrothed)other solid components of the ore. Flotation is based on the principlethat introducing a gas into a liquid containing solid particles ofdifferent materials suspended therein causes adherence of some gas tocertain suspended solids and not to others and makes the particleshaving the gas thus adhered thereto lighter than the liquid.Accordingly, they rise to the top of the liquid to form a froth.

Various flotation agents have been admixed with the suspension toimprove the frothing process. Such added agents are classed according tothe function to be performed: collectors, e.g., high carbon chaincompounds such as collectors for sulfide minerals including xanthates,thionocarbamates, and the like; frothers which impart the property offorming a stable froth, e.g., natural oils such as pine oil andeucalyptus oil; modifiers such as activators to induce flotation in thepresence of a collector, e.g., copper sulfate; depressants, e.g., sodiumcyanide, which tend to prevent a collector from functioning as such on amineral which it is desired to retain in the liquid, and therebydiscourage a substance from being carried up and forming a part of thefroth; pH regulators to produce optimum metallurgical results, e.g.,lime, soda ash and the like.

It is of importance to bear in mind that additives of the above type areselected for use according to the nature of the ore, the mineral soughtto be recovered, and the other additaments which are to be used incombination therewith.

An understanding of the phenomena which makes flotation a particularlyvaluable industrial operation is not essential to the practice of thepresent invention. They appear, however, to be largely associated withselective afl'mity of the surface of particulated solids, suspended in aliquid containing entrapped gas, for the liquid on one hand, the gas onthe other.

The flotation principle is applied in a number of mineral separationprocesses among which is the selective separation of such minerals assulfide copper minerals, sulfide zinc minerals, sulfide molybdenumminerals and others from sulfide iron minerals. The present inventionconcerns a novel class of compounds. These compounds can be employed ascollection agents in a flotation process. With some of these compoundsbetter recoveries are realized and with others, improved selectivity isachieved. Certain of these compounds produce improvement in bothaspects.

SUMMARY The present invention concerns novel compounds corresponding tothe formula wherein R represents H, a hydrocarbyl group, or aheterohydrocarbyl group, wherein said groups can be substituted with upto two functional groups and contain from 1 to 10 carbon atoms; R,represents an alkylene or heteroalkylene group having a heteroatomsubstituted in the carbon chain, and R represents a hydrocarbyl orheterohydrocarbyl group, except for aryl, wherein either of said groupscan be substituted except in the alpha position with up to twofunctional groups. The novel compounds can be prepared by the reactionof an amino alcohol with a xanthate ester and contacting the productproduced with an acyl halide. The novel compounds can be employed toimproved the flotation process of separating sulfide minerals from oresby employing an effective quantity of at least one of the novelcompounds set forth herein in the flotation process. The novel compoundsare also useful as fungicides and herbicides.

PREFERRED EMBODIMENTS The novel compounds of the present inventioncorrespond to the formula wherein R represents H, a hydrocarbyl groupselected from the group consisting of alkyl or alkenyl containing up to10 carbon atoms, alkaryl, aryl, aralkyl, cycloalkyl, cycloalkenyl,aralkenyl or acylalkyl groups, wherein the acyclic carbon chain portionspreferably contain up to 3 carbon atoms and the cyclic group containsfrom 5 to 10 carbon atoms and a heterohydrocarbyl radical selected fromthe group consisting of alkoxy, alkenyloxy, alkoxy carbonyl,alkoxycarbonylalkyl, aryloxy, arylalkoxy, alkylthio and arylthio groups,wherein said heterohydrocarbyl groups can contain up to two identical ordifferent functional groups preferably selected from the groupconsisting of halo, alkoxy, cyano, and di-loweralkylamino groups; R,represents an alkylene or heteroalkylene group containing up to 8 carbonatoms and wherein the hetero atom is substituted in the carbon chain andis preferably selected from the group consisting of wherein X is ahydrocarbyl or heterohydrocarbyl group and not H; preferably X is alower alkyl group containing up to 5 carbon atoms; and R represents ahydrocarbyl group selected from the group consisting of an alkyl oralkenyl group, preferably containing up to 8 carbon atoms, an aralkylgroup, preferably containing from 1 to 3 carbon atoms, in the alkylportion, and an alicyclic or cycloakenyl group, preferably containingfrom 3 to 8 carbon atoms, wherein said hydrocarbyl groups can besubstituted, except in the alpha position, with up to two identical ordiflerent functional groups preferably selected from the groupconsisting of alkoxy, halo, cyano, acetonyl and dilower alkylaminogroups. R, R, and R are further characterized in that the totalnumber'of carbon atoms in said groups preferably ranges from about 4 toabout 25.

The novel compounds as defined herein can be prepared, for example, byreacting an aminoalcohol with a xanthate ester to prepare ahydroxy-thionourethane and then acylating the HO-R -moiety with an acylhalide, anhydride, or ketene. The reactions can be represented asfollows:

The novel compounds as defined herein have a special utility asflotation collectors and can be employed in standard flotation processesto concentrate copper sulfide and other like minerals from sulfide oresin preference to iron sulfides In a flotation process a pulp is firstprepared by wet grinding a sulfide containing ore to a suitable sizewith or without a pH modifier. A suitable frothing agent is then added,e.g., pine oil, cresylic acid, polyalkoxyparaffin and the like. Aneffective quantity of a flotation collector compound as defined hereinis Example 1 A novel compound corresponding to the formula was preparedin the following manner.

To 30 grams (0.2 moles) of methyl isopropylxanthate was added 12.2 grams(0.2 moles) of 2-aminoethanol. The mixture became hot and there was avigorous evolution of methyl mercaptan. After an hour of heating on thesteam bath, the residual methyl mercaptan was removed by applying avacuum. The structure of the product, confirmed by infrared and NMRanalyses, corresponded to the formula The product was a viscous liquid.A sample of this product was distilled under vacuum and had a boilingpoint of 120- 122 C. at 0.7 mm. Hg.

A solution of 16.3 grams of the product prepared above, 10.2 grams ofacetic anhydride, and 8.1 ml. of pyridine in 100 ml. of absolute diethylether was let stand for a day. More ether was added and then the mixturewas washed twice with water, dilute l-lCl, and finally with saturatedaqueous NaH- C0 After drying over MgSO, and removing the solid byfiltration, the solvent was stripped off by heating to 75 C. under areduced pressure of 20 mm. The yield was 16.9 grams (76.5 percent yield)of the novel compound designated above. The structure of the newcompound was identified by infrared analysis. A sample of the compoundwas distilled under a reduced pressure and was found to have a boilingpoint of lO9ll2C.00.l mm.llg.

Example 2 A new compound within the scope of the invention definedherein and corresponding to the formula was prepared in the followingmanner: A solution of 16.3 grams of isopropyl2-hydroxyethylthionocarbamate in 25 ml. of 50 percent diketene/acetonewas let stand for a week. The oil obtained on addition of 100 ml. ofwater was taken up in ether. This extract was dried over MgSO The solidwas later removed by filtration and the ether removed by distillation,the last traces with a vacuum. The structure as set forth above wasconfirmed by infrared and NMR analyses. The yield was 89 percent. Thecalculated and actual elemental analysis for the product correspondingto the formula set forth above is Percent Example 3 Another novelcompound within the scope of the present invention is prepared in thefollowing manner. The reaction is set forth as:

The compound is prepared as follows.

To 15 grams (0.1 g. mole) of methyl isopropyl xanthate is added 14.5 g.(0.1 g. mole) of 2-aminoethyl pivalate and the mixture warmed. Whenmethyl mercaptan evolution ceases, the last traces are removed undervacuum. The residual oil is induced to crystallize and the resultingsolid-the new compoundis found to melt at 4849 C.

Example 4 A new compound corresponding to the formula was prepared inthe following manner.

A solution of 16.3 grams of isopropyl 2-hydroxyethylthionocarbamate (0.1mole), 7.9 gms. of pyridine (0.1 mole) in ml. of ether, was cooled andstirred. 13.6 grams (0.1 mole) of ethyl oxalyl chloride was added withcooling and stirring and when this was complete, the solution wasstirred for one hour. The ether solution was dried with Na SO filteredand stripped of ether by heating under a vacuum. The product yield was81 percent. The product was analyzed by both infrared and NMR analysis.The actual and calculated elemental analysis for the compound having theformula set forth above are:

Percent C H N Calculated... 45. 61 6.51 5.32 Actual- 44.0 6.50 5.80

Example 5 A new compound within the scope of the present invention wasprepared corresponding to the formula A starting material compoundcorresponding to the formula was prepared as follows: To 18.1 grams of2-(2-hydroxyethyl)- thioethylamine was added 22.5 grams of methylisopropylx anthate. The mixture was heated in a hot water bath to driveoff most of the evolved CH SH gas. The mixture was then heated to 65 C.under a reduced pressure of 20 mm. to remove the last traces of CH Sl-l.The yield was nearly quantitative. The structure of this startingmaterial was 4by infrared and NMR analysis. To 17.9 grams of theso-prepared starting material in 35 ml. of ether and 8.9 ml. of pyridinewas added 9.0 grams of acetic anhydride. After 20 hours, additionalether and a small quantity of methanol was added to convert theunreacted acetic anhydride present to methyl acetate. The reactionmixture was then treated with a dilute hydrochloric acid solution toremove the pyridine and then washed with aqueous Nal-lCO to remove theacids. The product mixture was then dried over MgSO filtered and theExample 7 Various species of flotation collector compounds within thescope of the present invention were employed in the recovery remainingether and the methyl acetate were removed under 5 of pp and molybdenumfr m a S lfide ore obtained from d d pressure f 4 b h i to 70 C 19 7grams or South America employing the following procedure: The ore abouta 93 percent yield of the product was obtained, Th sample was ground for5 minutes at 66 percent solids with no structure of the novel compoundcorresponding to that set reagents The p p Cohdmohed 8 minutes withforth above was continued by infrared and NMR analysis. Eleof a Speclficflotahoh collector compound and menu analysis gave 452 percent 3 percentand 0.13 lbs./ton of a standard frother. During the conditioningpercent. Calculated analysis for a compound corresponding to Penod the Pwas adlusted 5 3 value of 3909i The P p m above structure is (3,453percent percent and was then floated for seven minutes and the tailingsassayed for 3 percent copper and molybdenum. A standard flotationcollector consisting of a thionocarbamate compound corresponding to theExample 6 15 formula Other species of compounds within the scope of thepresent H s CH invention were prepared according to one of theprocedures g 3 set forth in Examples l4. The starting materialsconsisted of 1 2 a compound corresponding to the formula OH;

I ll HOR1NH-C-ORZ and an acylating agent which provided the 4: moiety ofthe novel compounds. R R the acylating agent, the empirical formula ofthe prepared compound, and the actual and calculated analysis for eachcompound are set forth in the following Table I. The method ofpreparation is listed in the method of preparation column and the numbercorresponds to one of the Examples 1-4. All the compounds were found topossess collector activity when employed in the flotation separation ofsulfide containing ores. 3 5

TABLE I Analysis, percent Method of prep- Calculated Actual aratioriCompound empirical R R3 Acylating agent C H N C H N i l CgHnNOaS lCHzCHz- --iPr (CH3C)2O 46.81 7.37 6.82 46.4 7.3 6. 8

CH; |OI l CuHnNOaS 1 CH-CHziPr (d C-):O b 59. 76 6.80 4.98 59.5 6.9 5.4

C-ZH5 (I) l C9HI1NO3S 1 CH2CH- CzHs (CH3C)2O 49.29 7.82 6. 39 49.4 8.24.9

CH3 H C HnNOaS 1 C H-CH: iPr (CH3C)2O 49. 29 7.82 6.39 48. 6 8.0 6. 5

if clzHggNo s 1 -C:HOC2H4 iPr (CH;):CHC)2O 55.14 8. 87 5. 36 51.4 9.85.3

H C9Ht7NO4S 4 CzH lPr C2H5O-C-Cl 45.94 7- 28 5.95 45.7 7 3 6.4

CH3 (I) C HirNOaS 1 HCHz- -iPr (CH3C-)2O 49.29 7.82 6.39 48.6 8.0 6.5

CH: (H) C1QH1QNO4S 4 CHCHriPr C'ZHflOC-Cl 48.17 7.68 5. 62 47.3 7.9 6.9

ll CiaHirNOaS 4 CQH4- iPi' rbC-Cl 58.40 6.41 5.24 58.6 6.4 7.1

II CuHziNOaS 1 -C5H1 C2H5 (CH3-C-)2O 53.41 8.56 5.66 53. 2 8.6 6. 2

i C1aHnNO4S 4 CzH iPr O-C-Cl 55.10 6.05 4.94 56.7 8.9 5. 3

was employed as a control. The specific collector compounds employed andresults are set forth in the following Table ll.

TABLE II Percent Percent Run Number Collector compound Ed 33:1 clfi l la ii recovered recovere ControL ControL. 0. 12 O. 281 84. 2 64. 4

cu coczurxcocmcnm 2 O CH; HS 0.09 0.234 87.0

OHCHFIL OCH(CHJ)E s o 0. 03 0. 23s 86. s

C2H5O1C|OC2H4NCOCH(CH3)2 l. l

Example 8 Example 9 Various novel collectors within the scope of thepresent invention were tested on a copper sulfide ore from theSouthwestern United States. The ore sample was ground for 4% minutes at59 percent solids with 2.0 lbs/ton of lime. The pulp was conditioned for2 minutes with an amount of a specific collector and 0.16 lbs/ton of astandard frother at a pH of 10.5. The pulp was then floated for 8%minutes and the tailings assayed for copper. The results obtained areset forth in the following Table III. The same control flotationcollector was employed as in Example 7.

In this example a copper-molybdenum sulfide containing ore from WesternUnited States was treated in a manner similar to that described inExamples 7 and 8.

A sample of ore was ground at 60 percent solids to 35 percent minus 200mesh Tyler. To the pulp was added 0.9 lbs/ton lime, 0.08 lbs/ton dieseloil, 0.01 lbs/ton of a collector compound to be tested and 0.06 lbs/tonfrother. The ore was floated for 8 minutes. Both the concentrate andtailings were filtered, dried and assayed for Mo and Cu. The samecontrol collector compound was employed as in Examples 7 and 8.

TABLE III Lbs. Percent Percent Saber Collector compound add gz i iaiiico r e ls'gl'jffifiilii::::::::::::::::::::::::::::::::31:33:: 3:933:??? 32:? 1 O 0 H HS 0. 008 0.324 60.1

C H5PJOCzH I IC Hol I OCH(CH )z (CHghCHii?OC H4OC H NQOCH(CH I'IS CH]OCzH410 OCH(CH 4 0 CH S 0. 025 0. 092 87. 2

CH3% OC IHCHQNE OCH(CH )3 CzH O( )OC H51 1( OCH(CH )g i JOC2H4I MJOCH(CH CH3COCuH1gNCOC2H5 8... 0 CH3 HS 0.13 0 110 85.5

CHi JOJJHCHQI I OCEKCHQQ CgH O 3 OC3H6.-\L(H:O CH(CH3)'23OCzH4NOCH(CH;)g

11 CH 0 CuH NQ O C3H5 0. 13 0. 118 84. 5

ll 0 HS The results obtained are shown in the accompanying Table IV.

prepare the indicated novel compound.

The xanthate starting materials employed herein in the preparation ofthe novel compounds, for example, as in Example 1, can be prepared in amanner well known in the art. For example, an alcohol corresponding toR,OH, wherein R is the same as defined hereinbefore, can be reacted asthe corresponding alkali metal alkoxide, with CS, to prepare a productcorresponding to the formula wherein M is the alkali metal ion. Theproduct can then be contacted with, for example, methyl chloride, toprepare the corresponding xanthate ester i R C-SCH;

Alcohols which may be employed include, for example, cyclohexanol,cyclohexenol, allyl alcohol, cinnamyl alcohol. 2-bromo-allyl alcohol;2,3,5-trimethyl-3-hexanol; 2,3,4- trimethyl-Z-hexanol and the like.

Acylating agents which can be used in preparing the novel compounds ofthe present invention can be prepared by converting carboxylic acids tothe corresponding acyl chloride by contacting said acids with thionylchloride by processes well known in the art. Carboxylic acids which maybe employed in clude, for example, cinnamic acid, a-bromocaproic acid,pelargonic acid, methacrylic acid, 3-cyanophenylacetic acid,cyclohexylacetic acid, cyanoacetic acid, Z-phenoxybutanoic acid,methoxyacetic acid and the like.

Other acylating agents which can be employed to prepare the novelcompounds include thiochloroformates such as and alkenylchloroformatessuch as O 0H2=c11-cH,o c'o1 and the like.

Other novel compounds may be prepared in a manner similar to thatdescribed in the foregoing examples. For example, a compoundcorresponding to the formula can be prepared by reacting ethylenimineand pivalic acid to prepare a compound corresponding to the formula(CH3)3CC CHQCH3XHQ and reacting this compound with methyl isopropylxanthate to Another compound corresponding to the formula is prepared byreacting 17.0 grams of aniosoyl chloride with 16.3 grams of ethyl2-hydroxyethylthionocarbamate to produce the indicated compound having amolecular weight of 283. Similarly, by employing 10.4 grams of crotonylchloride, 15.4 grams of crotonic anhydride, 13.8 grams of 2-chlorocrotonyl chloride, or 15.0 grams of 3-carbomethoxypropionylchloride instead of anisoyl chloride, compounds corresponding to thefollowing formula are prepared:

and

O H S respectively.

Other compounds within the scope of the present invention may beprepared by a method as defined herein by choosing various startingmaterials.

Various modifications may be made in the present invention withoutdeparting from the spirit or scope thereof for it is understood that weare limited only as defined in the appended claims.

What 1 claim is:

1. In a process of concentrating sulfide ores by flotation in thepresence of a flotation collector, the improvement which comprises:

a. subjecting the sulfide containing ore in the form of a pulp toflotation collector comprising a compound corresponding the formulawherein R represents H, a hydrocarbyl radical selected from the groupconsisting of alkyl or alkenyl containing up to 10 carbon atoms, aryl,alkaryl, aralkyl, cycloalkyl, cycloalkenyl, aralkenyl or acylalkylgroups wherein the acyclic carbon chain portion contains up to 3 carbonatoms and the cyclic groups contains from 5 to 10 carbon atoms, aheterohydrocarbyl selected from the group consisting of alkoxy,alkenyloxy, alkoxy carbonyl, alkoxycarbonylalkyl, aryloxy, alkylthio,arylthio, or oxyalkyl group; R represents a member selected 0 from thegroup consisting of an alkylene or heteroalkylene wherein X is a memberselected from the group consisting ofa hydrocarbyl or heterohydrocarbylradical wherein the hetero atom is substituted in the carbon chain; andR represents a hydrocarbyl selected from the group consisting of analkyl or alkenyl group, containing up to 8 carbon atoms, an aralkyl,containing from I to 3 carbon atoms in the alkyl portion, andanalicyclic or cycloakenyl group, containing from 3 to 8 carbon atoms,wherein R, R and R, are further characterized in that the total numberof carbon atoms in said groups range from about 4 to about 25.

2. The process as defined in claim 1 wherein R and R contain up to twofunctional groups other than in the alpha position of R selected fromthe group consisting of halo, alkoxy, cyano, acetonyl, ordi-loweralkylamino group.

3. The process as defined in claim 1 wherein X is a lower alkyl groupcontaining up to 5 carbon atoms.

4. The process as defined in claim 1 wherein from about 0.01 to about0.25 pound of compound per ton of sulfide ore pulp is employed.

5. The process defined in claim I wherein said compound consists of 0CH3 H S ll 1 a CH; OCHCH N- OCH(CH )2 6. The process defined in claim 1wherein said compound consists of r H s CH3C-OCH2CHZNCOCH(CH3):

7. The process as defined in claim 1 wherein said compound consists of 0CH H S 8. The process as defined in claim 1 wherein said compoundconsists of OH: H S

9. The process as defined in claim 1 wherein said compound consists of OH S

2. The process as defined in claim 1 wherein R and R2 contain up to twofunctional groups other than in the alpha position of R2, selected fromthe group consisting of halo, alkoxy, cyano, acetonyl, ordi-loweralkylamino group.
 3. The process as defined in claim 1 wherein Xis a lower alkyl group containing up to 5 carbon atoms.
 4. The processas defined in claim 1 wherein from about 0.01 to about 0.25 pound ofcompound per ton of sulfide ore pulp is employed.
 5. The process definedin claim 1 wherein said compound consists of
 6. The process defined inclaim 1 wherein said compound consists of
 7. The process as defined inclaim 1 wherein said compound consists of
 8. The process as defined inclaim 1 wherein said compound consists of
 9. The process as defined inclaim 1 wherein said compound consists of
 10. The process as defined inclaim 1 wherein said compound consists of